Rotary impact tool



June 24, 194L P. VAN SITTERT ETAL ROTARY IMPACT TQOL Filed Aug. 6, 195'? Patented-June 24, 194,1

v UNITED y STATE ROTARY IMPACT TOOL Paul van Sittert and Spencer B. Maurer, Cleveland Heights, Ohio, assignors to The Cleveland Pneumatic Tool Company; Cleveland, Ohio, a

corporation o! Ohio Applicants August s, 1937, seriai'No. 151,744

` (ci. 1oz-sos) 2 Claims.

This `invention relatesbroadly to rotary tools, but more particularly to :tluid actuated reversible rotary tools ci the impact type. f

One object oi this invention is to produce a rotary tool or motor adaptedto engage the work ior normally rotating the same, the tool being provided with means automatically operable for imparting a rapid succession of rotative impacts to the work. 4

Another object o! the invention is to produce an improved rotary tool especially fitted for setting or removing nuts, bolts or the like. and constituting a simple assemblyV which is strong, durable and eilicient.

Other objects and advantages more or less anclllary to the foregoing and the manner in which the various'objects are attained, reside in the specific construction and aggroupment of the elements peculiar toV this structure, as will become in a plane indicated by line 2-2 in Fig. 1 and.

illustrating parts in different positions.

Referring to the drawing in which like symbols designate corresponding -parts throughout the several views, represents generally a reversible rotary air motor of any suitable design. For purpose of illustration the motor is shown to include a cylinder housing II having a rotor I2 rotatable therein and carrying the usual blades I3 on which the compressed air or motive fluid may beadmitted for actuating the rotor in either direction. Keeping the rotor I2 in position against longitudinal movement. there are two stationary bearing plates I4 and I5 rigidly clamped to the cylinder housing Il. Extending rearwardly from the rotor or toward the left in Fig. 1, there is a shafted end I6 journaled within a ball bearing I1, which bearing is held in position within the plate Il by a retaining nut I3. l

The cylinder housing II is actually clamped, by bolts I3, between two housings, one a valve housing and the other a iront housing 2 I. Secured tothe valve housing 20 by cap screws 22, there is a back head or handle 23equipped'with a motive fluid connection 2l. From the connection 2l, the motive uid may be admitted into the valve housing 20 through a port 2i, which is controlled by a throttle valve 23 operable by a trigger 21 and a rod 23. .i Rotatably mounted within the valve housing 20, there is a four way valve 23 having pressure iiuid admitted thereto from the port 25 through a port 30. 'Ihis valve is of a standard type operable for controlling the admission of the pressure iiuid into the cylinder housing II through either a port 3I or 32 for actuating the motor in either direction. It is to be understood that the motor described above ior purpose of illustration, may be of any suitable type, and since that motor does not form a part of this invention, no further description is thought necessary other than pointing out that the invention hereinafter described is shown to be used with a reversible motor, but couldljust as well be adapted to a non-reversible motor.

Referring now more particularly to the invention which is generally contained within the front housing 2 I, 33 represents a drive shaft extending forwardly from the rotorll2 and shown in the drawing to be an integral part oi' the rotor. In practice, questions of design and arrangement oi parts may require the shaft 33 to be independent oi.' the rotor, and be coupled therewith' by any suitable means such as gear, splines or the like. In the present construction, the driving shaft 33 is journaled within a ball bearing 34 mounted within the bearing plate Ill;

shoulder or step 31 engaging one side of the 'I'he front end portion of the shaft 33 is formed with straight longitudinally disposed splines 35, interlocked with similar splines formed internally oi a driving head 36, which head is thereby carried by the shaft 33 for rotation therewith. To maintain the head 36 against longitudinal movement, the shaft 33 is Iformed with an annular head while the other side thereof is engaged by a washer 33 secured to the shaft 33 by a screw 39. The driving head 33 is accurately machined to pivotally receive two sets of pawls or weights, one set comprising two pawls 4I) and 4I diametrically opposed to each other, and thevother set comprising two pawls 42 and 43 also diametrically opposed to each other. These pawls extend longitudinally oi the head 36 `in end engagement with the shoulder 31 formed on the shaft 33 and the washer 33, and are pivotally mounted within the head as clearly show.- in Fig. 3. Between the pawls 40 and 42 and the pawls 4I and 43,

the head `is cut away to make room for the pawls when in a retracted position as shown in Fig. 2, and enables them when in this position to remain within an imaginary circle of a diameter email to the normal diameter of the head 38. Extending from each pawl outside of the washer 36, there is a short stem or pin 4Q. The pawl 4673 is connected to the pawl d@ by a tension spring d5 having its ends attached to the respective pin of? the pawls, while the pawl di is simliar-ly cemented to the pawl 32 by a tension spring 56.

tatabie within the front housing 2i, there is a cup shaped work engaging member or driven head di within which is rotatably mounted the driving head This driven head has its rear end supported by a plate d@ which is formed with a stem QQ journaled within a ball bearing 5t. Toward the front, the driven head d1 is reduced to form a stem iii journaled within a ball bearing 5E, and a shank end 5S of polygonal shape protruding outside ot the front housing to receive a work engaging socket 5t detachably secured thereon by a spring pressed plunger 55.

Inside oi the cup shaped drlvenhead All, there are formed two diametrically opposed lugs or clutch jaws 56 and 51 which extend longitudinally of the head a distance equal to the width of the pawls carried by the driving head. These lugs are preferably made an integral part of the driven head, and each has two inclined side walls or striking faces 58 and 5@ with which the pawls are capable of engagement.

In the operation of the device, let it be assumed that the throttle valve 251 is open and that motive fluid is admitted into the cylinder housing il through the valve 29 and the port 3i for imparting rotation to the rotor in a counterclockwise direction in Figs. 2 and 3, and that the work to be driven by the motor is a bolt 60 operatively engaged by the socket 5d. In this instance, it will be understood that the rotation of the rotor is transmitted to the driving head 36 through the shaft 33. During the rotation of the head 36, the tension of the springs 45 and 46 will be overcome by the centrifugal force applied to the four pawls carried by the head 36, thus causing the pawls to move into engagement with the lugs 56 and 51. When the rotor is rotating in a counterclockwise direction in Figs. 2 and 3, the pawls 42 and 43 will engage the side walls 59 of the lugs 56 and 51, while the pawls 40 and 4l will simply ride theA lugs as shown in Fig. 3. When the driven head 41 is not subjected to a torque resistance, that is, when the bolt 60 is free to rotate, the pawls 42 and 43 will remain in engagement with the lugs 5G and 51 respectively, thereby transmitting rotary motion to the driven head 41 and in turn to the work or bolt Bd.

After the bolt is initially set, it tends to resist further rotation of the driven head 41, increasing thereby the torque resistance of the head. This increased resistance will gradually retard the speed of the motor, thereby reducing the centrifugal force applied to the pawls and causing the pawls to assume the position shown in Fig. 2, that is out of engagement with the lugs 56 and 51 due to theaction of the springs 45 and 46. The contact angle between the pawls and the lugs 56 and 51 is calculated to be somewhat smaller than the corresponding friction angle, allowing thereby a. comparatively free pivotal movement of the pawls due to the action of the springs 56 and 51, and prevent-ing the contact angle to cause the disengagement or camming movement ot the pawls away from the lugs during normal operation.

Subsequent to the disengagement of the pawls aaeaeaa d2 and it with thelugs E36 and 5l, the rotor new disengaged from the driven head 6l' will again regain its maximum speed, imparting thereby e. centrifugal force to the pawls, which force will overcome the eiort of the springs Q5 and QG and cause the sudden reengagement of the pawls d@ and i3 with the striking faces 5g of the lugs 56 and 5l?, thereby imparting a rotative impact to the driven head il and consequently to the work or bolt 653. This sudden reengagement of the pawls with the lugs of the driven head d? will again retard the speed of the rotor, reducing thereby the centrifugal force imparted to the pawls and causing their disengagement due to the action of the springs 55 and 65 in the manner above described.

From the foregoing description, it will be understood that the pawls di, 32, d3, and l together with the lugs 55 and 5l form a clutch mechanism .wherein the pawls constitute driving clutch means or jaws centrifugally movable into operaand 5i, and capable of release to enable relative rotation between the heads 35 and 5l. When the rotor reaches its maximum speed, the driving jaws d2 and $3 are automatically thrown into engagement with the driven head or work engaging member l1 for imparting a continuous rotation to the work until the rotation is materially resisted by the work. In this instance, the driving jaws will again automatically be disengaged from the work engaging member, allowing the rotor to again regain its maximum speed for causing the reengagement of the jaws, and consequently of the rotor with the work. Through this engagement and disengagement of the jaws, the work engaging member is subjected to a rapid succession of rotative impacts which will continue as long as the throttle valve 26 is left open;

When the speed of the motor is retarded by an increased torque resistance applied thereto which will subsequently enable the driving jaws to move out of engagement, the motive fluid admitted into the motor will increase in pressure, consequently building up energy in the motor which will be released upon the disengagement of the jaws for imparting rotation to the rotor. This increased energy will cause the rotor to immediately regain its maximum speed for effecting the reengagement of the jaws and the consequential transmission of a rotative impact to the driven head 41 of an intensity greater than that resulting from the normal, rotation of the rotor.

When it is desired to drive the work in the other direction, the valve 29 may be positioned for admitting motive uid into the cylinder Il through the port 32. In this instance the driving head 36 will rotate in a clockwise direction in Figs. 2 and 3 causing the pawls or jaws 40 and 4I to strike the side wall 58 of the lugs or jaws 56 and 51 for driving the work engaging member in the manner as above described.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or conning and it is to be further understood that various rearrangements of parts and modifications of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

1. In a device of the character described, the combination of a driving head having rotation imparted thereto in either direction, a rotatable driven head, clutch jaws stationary von said driven head, two sets of driving jaws carried by said driving head for rotation therewith and pivotal movement relative thereto on axes parallel to the center axis thereof, said driving jaws being centrifugally pivoted into operative engagement with said clutch jaws one set during rotation of said driving head in one direction and the other set during rotation of said driving head in the other direction, said driving jaws being capable of release to enable relative rotation between said clutch and driving jaws, and means automatically effecting said release upon a predetermined reduction in the rotary speed of said driving laws.

2. in a device `of the character described, the combination of a driving head having rotation l imparted thereto in either direction, a rotatable driven head, clutch means between said heads including weights pivotally carried by said driv` ing head for rotation therewith and pivotal movement relative thereto on axes parallel to the cen- 10 and disposed in a manner enabling during normal conditions of operation transmission o1" rotation between said heads and under abnormal conditions of operation transmission of rotary impacts to said driven head irrespective of the direction l5 of rotation of said driving head.

PAUL VAN SI'ITERT. SPENCER B. MAURER. 

